芴酮-芳香醛-双腙的合成、晶体结构及光限幅性能

合成了4种新的标题化合物,通过红外光谱、核磁共振、质谱及元素分析对它们结构进行了表征,并通过单晶X射线衍射确定了芴酮-N,N-二甲基苯甲醛-双腙的结构,结果表明该晶体为正交晶系,属Pbca空间群,具有较大的共轭体系和良好的平面性.采用Z-扫描技术测试了4种化合物的光限幅性能,研究表明其中3种化合物对532 nm激光有良好的光限幅性能,其双光子吸收截面分别为3.19×10-46、3.96×10-46和4.31×10-46 cm4*s/photon.     

Relationship between crystal structure and microwave dielectric properties of melilite-type ceramic

Crystal structure–microwave dielectric property relations in the melilite-type Ba₂(Mg_1−xZn_x)Si₂O₇ ceramics were investigated in this study. The formation of a secondary phase was not detected over the whole composition range. Also, the lattice parameter, a, of the solid solutions decreased linearly with increasing the composition x, while the lattice parameter, c, was increased by the Zn substitution for Mg. Also, the covalency of the MgO bond increased from 26 to 35% in the composition range of 0–0.75. Moreover, the covalency of the ZnO bond increased in the composition range of 0.25–1, while that of SiO bonds in the SiO₄ tetrahedron remained approximately constant over the whole composition range. The dielectric constants (ɛ_r) of the solid solutions were on the order of approximately 7.5, and the quality factors (Q·f) of the solid solutions increased with increasing the composition x. The temperature coefficient of resonant frequency (τ_f) of the solid solutions varied from −62 to −74 ppm/°C with increasing the composition x; therefore, the Zn substitution for Mg was not effective in improving the τ_f value in this system.     

Physico-chemical properties of ceramic pigments for high-temperature application

Heat resistant coatings are required primarily for stacks, exhaust pipes, reactors, space crafts and similar equipments that are permanently or occasionally exposed to elevated temperatures. High-temperature coatings are generally based on silicone resin with ceramic and metallic pigments. In this study, iron oxide, cobalt oxide (thermo chromic compound) and aluminum oxide are used for the preparation of four new types of coloured pigments. The thermal resistant characteristics of these ceramic pigments were studied by differential thermal analysis, thermo gravimetric analysis and differential scanning calorimetric analysis. These ceramic pigments are found to be thermally stable up to 400 °C.     

Synthesis, crystal structure, optical properties, DNA-binding and cell imaging of an organic chromophore

An organic chromophore (4-[N, N- bis(2′-chloroethyl)anilino] ethenyl N-methyl pyridinium-N- methyl iodide) L was synthesized and fully characterized by elemental analysis, IR, ¹HNMR spectra and single crystal X-ray diffraction analysis. One and two-photon fluorescence spectra for it were studied. Interestingly, L exhibited obvious two-photon absorption in the range from 700-850 nm in DMSO solution. The interactions between the chromophore and calf thymus DNA were investigated by absorption, fluorescence spectra and viscosity experiments. The results showed that the chromophore could interact with DNA in the mode of intercalation and be effectively used as fluorescent staining dye for cell imaging applications. Furthermore, the cell viability data for MCF-7 (Human breast carcinoma) cells indicated that the low-micromolar concentrations of the L are essentially non-toxic and can be applied in brighter two-photon fluorescent (TPF) bioimaging.     

Hydrothermal synthesis,crystal structure and optical properties of a 2-D heterometallic iodoplumbate

A novel two-dimensional heterometallic iodoplumbate, [Pb₃I₁₀Cu₄(phen)₂]_n (phen = 1,10-phenanthroline) constructed from [Pb₃I₁₀]^4? iodoplumbate chains and [Cu₂I₄(phen)]^2? entities has been hydrothermally synthesized and structurally characterized. The solid compound exhibits an intriguing semiconducting property with E_g = 2.62 eV. The thermochromic behavior of the compound has been also studied.     

Production of ceramic pigments with diopside structure from TALC

The results of investigation of synthesis of ceramic pigments with diopside structure are presented. Two reactions of diopside production are considered. It is indicated that the use of natural talc mineral makes it possible to lower the expense of pigment production and expand the pigment color range.     

The structural evolution and optical properties of Mg1-xZnxAl1.8Cr0.2O4 pink ceramic pigments

In this work, pink ceramic pigments based on the composition of Mg_1-xZn_xAl_1.8Cr_0.2O₄(x = 0.0,0.3,0.5,0.7,1.0) were synthesized by using a gel polymerization method. We focused on studying the effect of A-site ion doping on the random cation distribution, microstructure and optical absorption performance. Field Scanning electron microscopy (FESEM), X-ray diffraction (XRD) and the Rietveld refinement method with a GSAS program were applied for micromorphology and cation distribution analyses. The optical performance of the pigments was studied by UV–vis and CIE L*a*b* spectrophotometry. All samples had a single spinel phase within the calcination temperature range of 800 °C–1400 °C and the primary grain size of the synthesized pigments were approximately 0.5–1 μm. The ion distribution in the tetrahedron and octahedron was largely dependent upon the calcining temperature and composition. The oxygen parameter, cell parameter, and T-O and M-O band lengths also varied with the cation distribution, leading to a change in the spinel structure and octahedron crystal field parameter and ultimately changing the optical absorption properties of the synthetic pigments. This study lays the foundation for subsequent studies of colour modification in ceramics.     

Preparation and enhanced ferromagnetic, semi-conductive, and optical properties of Co-doped ZnO rod arrays

In this study, co-doped ZnO rod arrays with wurtzite crystal structure were successfully prepared on zinc substrate by the co-precipitation method. The results of crystal analysis indicated that the dopant Co²⁺ was incorporated into ZnO crystal. Photoluminescence (PL) spectra and magnetization curves proved that their PL intensity and ferromagnetism were increased with the increase of Co²⁺ concentrations in a ZnO host. Current?Cvoltage characteristic curves of Co-doped ZnO rod arrays indicated that as-prepared samples were n-type semiconductors. Co-doped ZnO rod arrays could be envisioned to detect diseases and bacteria based on these properties.     

Polypropylene/linear low‐density polyethylene blends: Morphology,crystal structure,optical, and mechanical properties

The morphology, crystal structure, crystallization behavior, optical, and mechanical properties of isotactic polypropylene (iPP) blended with metallocene linear low‐density polyethylene (mLLDPE) and Ziegler–Natta linear low‐density polyethylene (zLLDPE), with and without nucleating agents, were investigated. The correlation between the structures and optical properties was investigated. The addition of linear low‐density polyethylenes (LLDPEs), nucleating agents, and poly(ethylene‐co‐octene) (POE) had little influence on the crystal form of the iPP. The growth along the b axis was favorable in the presence of nucleating agents and LLDPEs. The LLDPEs led to much finer crystal morphologies, and the nucleating agents further prohibited spherulite formation; consequently, light scattering from the bulk crystalline structure was reduced. In all blends, biphase morphology was observed, and POE could improve the adhesion between the iPP and mLLDPE. After blending with LLDPEs, the haze and stiffness decreased, and the gloss increased. mLLDPE enhanced the toughness whereas zLLDPE had a slight influence on it. The nucleating agents decreased the haze, increased the gloss more, and ameliorated the stiffness; however, they changed the toughness little. POE increased the toughness of the blend significantly, accompanied by a much lower haze, higher gloss, and almost the same stiffness. When the concentration of 1,3 : 2,4‐bis(3,4‐dimethyl‐benzylidene sorbitol) exceeded 0.25 wt %, the optical properties and mechanical properties leveled off. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of crystal size of Yellow 13-type pigments on optical and rheological properties of lithographic inks

Use of a modern diffractometer and detailed knowledge of the crystal lattice structure have improved ability to size crystals of CI Pigment Yellow 13-type pigments. This has enabled confirmation and refinement of correlations observed in earlier work between crystal sizes and optical and rheological properties of commercially available pigments in lithographic inks. The correlations indicate that the dispersion procedures used have produced inks in which the pigments exist substantially as individually dispersed crystals. The correlations also indicate that the crystals of the commercially available pigments are effectively perfect. An alternative explanation on the basis that the various pigments have similar degrees of aggregation and imperfection of crystals is also possible, but improbable due to the widely different compositions and sources of the pigments. Whether or not abietyl resin added to improve dispersibility of pigment remains on the crystal surfaces in inks has not been resolved.     

An investigation of angle-dependent optical properties of multi-layer structure pigments formed by metal-oxide-coated mica

The angle-dependent pigments with mica/TiO₂/Fe₂O₃, mica/TiO₂/Cr₂O₃ and mica/TiO₂/Co₂O₃ three-layer structure and with mica/TiO₂/Cr₂O₃/Fe₂O₃, mica/TiO₂/SiO₂/Fe₂O₃ and mica/TiO₂/SiO₂/Co₂O₃ four-layer structure were both prepared by the conventional wet chemical method. The obtained pigments were formed by precipitating different ions, such as Cr³⁺, Fe³⁺, Co²⁺ and SiO₃²⁻ on the pretreated substrates, mica titanium. The comparative optical effects of three-layer and four-layer structure pigments are investigated in detail by using the five angles' spectrophotometer. The results show that the angle-dependent effect and reflection rate of the pigment were improved by the increasing coated layers from three to four-layer structure. The possible mechanism was also discussed in this paper.     

Sintering behaviour and properties of magnesium orthosilicate-hydroxyapatite ceramic

The effect of pressureless sintering on the properties of magnesium orthosilicate-hydroxyapatite (MO-HA) ceramic has been studied. The amount of MO composition in the green body was varied from 10 wt% to 50 wt% through mechanical ball milling and was subsequently sintered at varying temperatures in air atmosphere from 1000 °C to 1300 °C for 2 h. The magnesium orthosilicate phase was stable during sintering but the hydroxyapatite phase decomposed to tricalcium phosphate. The MO-HA composites generally exhibited lower mechanical properties across all the investigated composition. Nevertheless, a high fracture toughness of 2.5 MPam^1/2 was recorded for sintered body that contained 20 wt% MO. This finding indicates the potential of this ceramic composite to be used for biomedical applications.     

Synthesis and characterization of (Pr,Ce)-ZrSiO4 ceramic pigments: The properties of the pigments and the effect of Ce

A series of (Pr, Ce)-ZrSiO₄ ceramic pigments were synthesized and characterized using XRD, SEM, EDS, XPS, XRF, colorimeter, and a UV-VIS-NIR spectrometer. The prepared pigments were mainly composed of the zircon phase and were well crystallized. Only a specific amount of Pr was incorporated into the ZrSiO₄ lattice. Compared with Pr, Ce was almost completely incorporated into the ZrSiO₄ lattice and was homogeneously distributed within the pigment particles. The dopant Ce reduced the amount of Pr dissolved in the ZrSiO₄ lattice and thus caused the b* values of the samples to decrease slightly. Meanwhile, the presence of Ce induced an apparent increase in red tone in the samples. The enhanced red tone resulted primarily from an increase in the absorption of light with wavelengths between 500 and 565 nm. High-temperature stability analysis demonstrated that it is feasible to improve the tone of Pr-ZrSiO₄ pigment by doping with Ce.     

Preparation,crystal structure and luminescence properties of red-emitting Lu3Al5O12: Mn4+ ceramic phosphor

A series of red-emitting Mn⁴⁺ doped Lu₃Al₅O₁₂ (LuAG) ceramic phosphors were successfully prepared by a simple solid-state reaction method in a high-temperature muffle. MgO was co-doped as sintering aids and Mg²⁺ ions helped to realize the charge balance. The relations between the luminescence properties, crystal structures and the microstructures were well established. Results indicated that MgO promoted the densification of the ceramics as the specimens’ relative densities were up to 99%. Moreover, the substitution of Al³⁺ with Mg²⁺ have changed crystal structures and further affected the luminescent properties. Overall, the obtained ceramic phosphors showed strong red-light emission under excitation of ultraviolet and blue light. By optimizing the Mg²⁺ and Mn⁴⁺ concentration, a quantum efficiency (QE) as high as 47.8% can be achieved under the excitation of 460 nm light, indicating that the LuAG: Mn⁴⁺ ceramic phosphors are promising candidates for WLEDs applications.     

Karrooite green pigments doped with Co and Zn: Synthesis,color properties and stability in ceramic glazes

The solid-state synthesis and stabilization of Co doped (Mg_1−xCo_xTi₂O₅), Zn doped (Mg_1−xZn_xTi₂O₅) and Co- and Zn-codoped karrooite solid solutions (Mg_0.8−xZn_0.2Co_xTi₂O₅ and (Mg_0.5Zn_0.5)_1−xCo_xTi₂O₅) were investigated. In addition, the optical spectra, color properties and technological performance of (Co,Zn)-karrooite compositions as new green ceramic pigments were also analyzed. XRD characterization revealed for the first time the high solid solubility of Zn²⁺ in MgTi₂O₅ karrooite at 1200 ºC (between 60 and 80 mol% per Mg or karrooite formula unit). In contrast, the reactivity and stabilization of karrooite phase decreased in the case of Co²⁺ doping. Interestingly, codoping with Zn²⁺ ions at high molar ratios (Zn:Mg ratio equal to 1:1) enhanced the reactivity and enabled the stabilization of (Co,Zn)-MgTi₂O₅ karrooite solid solutions, even with high Co²⁺ loadings (20 mol% per karrooite formula unit). The (Co,Zn)-MgTi₂O₅ pigments exhibited yellowish-green colors associated to Co²⁺ ions allocated in octahedral M1 and M2 sites of karrooite lattice, and becoming more intense and less yellow the higher the Co content. However, Zn²⁺ codoping produced less saturated green colors with similar green but lower yellowish hues. The obtained pigments were not stable enough within the tested ceramic glazes, giving rise to turquoise colorations due to cobalt leaching and incorporation into tetrahedral sites of the glassy phase. The stability of Co-karrooite green pigments was higher in a Ca- and Zn-enriched ceramic glaze (B) fired at a higher temperature (1050 °C).